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caspert79
Joined: 31 Oct 2010 Posts: 2926 Location: The Netherlands
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Posted: Wed Oct 14, 2020 12:22 pm Post subject: Nikon LS-20e scanner lens |
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caspert79 wrote:
I just opened up an old Nikon LS-20e film scanner and took out the tiny lens.
Does anybody know how to determine the correct distance between the lens and the camera sensor?
I want to try to use it in a macro setup. |
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Ultrapix
Joined: 06 Jan 2012 Posts: 551 Location: Italy
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Posted: Wed Oct 14, 2020 12:26 pm Post subject: |
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Ultrapix wrote:
point the lens towards the sun, or in any case an object at infinity; place a sheet of white paper behind the optics and measure the distance; the calculation of the focal length is complex, because you would need to know the position of the front nodal point (usually inside the optics), but you can have a rough idea of the space needed; for macro, that distance has to be increased proportionally |
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caspert79
Joined: 31 Oct 2010 Posts: 2926 Location: The Netherlands
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Posted: Wed Oct 14, 2020 12:37 pm Post subject: |
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caspert79 wrote:
Thanks. A rough idea is all I need. |
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Ray Parkhurst
Joined: 04 Jul 2011 Posts: 497 Location: Santa Clara, CA, USA
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Posted: Fri Oct 16, 2020 3:20 am Post subject: |
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Ray Parkhurst wrote:
Why not just measure the distance from the lens to the sensor in the LS20 you took it out of? _________________ ...See my Numismatic Photography website at: http://www.macrocoins.com
...Primary Studio Cameras: Sony A7Rm4 and Canon HRT2i
...Go-To studio lenses: Nikon 95mm and 105mm Printing-Nikkors; Schneider 85mm Macro-Varon; Nikon 5x, 10x, and 20x Measuring Microscope Objectives; Mitutoyo BD Plan Apo 50x Microscope Objective
...My Go-To Walkaround Lenses: Laowa 60mm Super Macro; Nikon 28-105D (in manual mode for macro); |
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caspert79
Joined: 31 Oct 2010 Posts: 2926 Location: The Netherlands
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Posted: Fri Oct 16, 2020 4:28 am Post subject: |
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caspert79 wrote:
Ray Parkhurst wrote: |
Why not just measure the distance from the lens to the sensor in the LS20 you took it out of? |
It's very hard to measure, because the lens is covered, there is only a slit and a mirror. |
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Ultrapix
Joined: 06 Jan 2012 Posts: 551 Location: Italy
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Posted: Fri Oct 16, 2020 10:55 am Post subject: |
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Ultrapix wrote:
By the way, I guess that a scanner lens only covers a very tiny area (hence the necessity of scanning the original), so I am really curious to know what you can do with it in macro, where the covered area obviously grows... |
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caspert79
Joined: 31 Oct 2010 Posts: 2926 Location: The Netherlands
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Posted: Fri Oct 16, 2020 11:10 am Post subject: |
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caspert79 wrote:
Ultrapix wrote: |
By the way, I guess that a scanner lens only covers a very tiny area (hence the necessity of scanning the original), so I am really curious to know what you can do with it in macro, where the covered area obviously grows... |
It could very well be that it doesn’t cover. The Coolscan iv does, but I’m not sure about this one. |
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dickb
Joined: 04 Apr 2008 Posts: 821
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Posted: Fri Oct 16, 2020 12:40 pm Post subject: |
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dickb wrote:
This type of scanner lens is designed to scan the width of 35mm film (ie 24mm) onto a line sensor. I don't know how large this sensor is in the LS20, but in the later LS40/4000 series it is a 32mm long sensor. In that scanner the lens is designed for 32/24=1.33x magnification with an image circle of 32mm.
The image circle will be a bit larger than that design minimum of 32mm at 1.33x and will be larger still when used at higher magnidfications.
http://www.savazzi.net/photography/scanner_nikkor_40mm.html
and
https://www.closeuphotography.com/scanner-nikkor-ed-7-element-lens
are descriptions of the LS40 lens, the later ED element version of the Nikon lens out of 35mm scanners. |
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Ray Parkhurst
Joined: 04 Jul 2011 Posts: 497 Location: Santa Clara, CA, USA
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Posted: Fri Oct 16, 2020 2:32 pm Post subject: |
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Ray Parkhurst wrote:
I've had good results from the LS20 / LS30, which use the same lens. The LS40 is different/bigger/has ED elements. The LS20 does cover 24mm so is good on APS-C. at ~0.7:1 reversed and even better at 1.33x forward. _________________ ...See my Numismatic Photography website at: http://www.macrocoins.com
...Primary Studio Cameras: Sony A7Rm4 and Canon HRT2i
...Go-To studio lenses: Nikon 95mm and 105mm Printing-Nikkors; Schneider 85mm Macro-Varon; Nikon 5x, 10x, and 20x Measuring Microscope Objectives; Mitutoyo BD Plan Apo 50x Microscope Objective
...My Go-To Walkaround Lenses: Laowa 60mm Super Macro; Nikon 28-105D (in manual mode for macro); |
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